<nz-layout>
  <nz-header>
    <div class="header-box">问卷调查系统</div>
  </nz-header>
  <nz-layout>
    <nz-sider>
      <survey-menu></survey-menu>
    </nz-sider>
    <nz-content> <router-outlet></router-outlet></nz-content>
  </nz-layout>
</nz-layout>